Download a new firmware image for your ESU-BRIDGE. Firmware can be found near the bottom of the ESU-BRIDGE product page. Note: Firmware images are large - in the 500MB range. Using a high speed connection is strongly recommended.

Power off your ESU-BRIDGE and carefully remove the micro SD card.

Insert the micro SD card into an SD card adapter, and insert into an SD card reader in your PC or Mac.

Save any changes you've made to protothrottle-config.txt and wireless-config.txt from the card, just so you have a reference for step 11, where you need to change the configuration back. It's not recommended to directly overwrite the new configuration files, since options may have changed.

Run the Etcher installer you downloaded earlier.

Click the blue "Select image" button from Etcher, and select the .zip file you downloaded earlier.

Once you have correctly identified the firmware image, click the blue "Select drive" button. BE VERY CAREFUL HERE TO SELECT YOUR MICRO SD CARD. SELECTING THE WRONG DISK WILL CAUSE ETCHER TO OVERWRITE THAT DISK IRRECOVERABLY.

During the process, Windows may pop up a bunch of "Drive (letter) needs to be formatted" messages. Just cancel out of all of them.

Once Etcher completes flashing, be sure to change the configuration files again if necessary. ESU users should not need to change from the defaults, but Digitrax and JMRI users will need to modify the configuration to match their setup.